Method of and apparatus for impregnating wood



W. C. ZELLER.

METHOD OF AND APPARATUS FOR IMPREGNATING WOOD.

APPLlCATiON FILED MAY 20, 1921.

Patented Dec. 12, 1922.-

INVENTOR BYk'nL ATTORN Y W. C. ZELLER- METHOD or AND APPARATUS Eon IMPRYE'GNATING woon.v

APPLICATION FILED MAY 20, I921.

Patented Dec; 12, 1922. A

2 SHEETS-SHEET 2.

INVENTOR n NEY Patented cc. 12, 1922.

1,438,471 FFHQE.

WILLIAM eznnnna, or rnmn iaoY, nnw mnsnx, ASSIGNOR To ERNEST o.

DRAPER, or new YORK, n. Y.

METHOD OF AND APPARATUS FOR IMPREGNATING. WOOD.

Application filed may 20,

To all whom it may concern:

Be it known that 1, WILLIAM C. ZELLER, a citizen of the United States, and a resident of Perth Amboy, county of Middlesex and State of New Jersey, have invented certain new and useful Improvements in Methods of and Apparatus for Impregnating Wood, of which the following is a specification.

This invention relates to an improved method of and apparatus for impregnating with preservative piling, posts, poles and similar pieces of timber.

The invention is designed to provide a method and apparatus which is applicable particularly to those cases where it is only necessary to impregnate a comparatively small portion in length of a piece of timber, as, for instance, in the case of piling where it is only necessary to impregnate with preservative the upper portion of the stick or that portion which is not driven into the mud or ground; and in the case of telephone or telegraph poles in which it is particularly desirable to impregnate that portion which is in the ground and about one foot above the ground. By confining the treatment to these portions, it is possible to effect a considerable saving, as the expense of impregnating the remainder of the pile or pole is avoided. It is also possible, with my method and apparatus, to give to one part of the timber a complete or nearly complete impregnation, and to give to the remainder a slight or surface impregnation.

Considered as a method, my invention is characterized by" the facts that the whole timber is placed in a closed retort, and that there is maintained within the retort around that portion of the timber to be treated a mixture of air and preservative in finely divided form, while that portion of the timber which is not to be treated is maintained surrounded by air which is substantially free of preservative; the contents of the retort being maintained under pressure or under varying degrees of pressure while the process of impregnation is going on.

The apparatus for carrying out my invention may be modified in many respects, butin its preferred form includes a retort adapted to receive the whole timber, preferably in a substantially horizontal position, said retort beingprovided with means for injecting into and withdrawing from its inside adjacent that portion of the timber which is 1921. Serial No. 471,129.

to be treated a mixture of air and preservative in finely divided form, and also preferably with means for controlling the pressures existing within the retort by reason of the injection andv withdrawal of air and preservative. By thus causing a mixture of air and preservative in finely divided form. to flow thru only that portion of the retort in which the portion-of the timber to be impregnated is located, the air trapped in the other part or parts of the retort is maintained substantially free of preservative and the portion of the timber surroundedby that air is not impregnated.

Experience has shown that localized impregnation of the timber can be obtained by m method of apparatus under pressure wlthout the use of partitions or gaskets of any kind. Moreover, my invention permits piles, poles and other long timbers to be given alocalized pressure impregnating treatment while said timbers are in a substantially horizontal position, a fact which leads to important economies over methods of an apparatus for impregnating which require that the timbers shall be located in a substantially vertical position while impregnation is taking place.

One form of apparatus for carrying out the invention is illustrated in the accompanying drawings, in which Figure 1 is a general view showing the relation of the different elements of the apparatus and illustrating its manner of use. Figure 2 is an enlarged elevation, somewhat diagrammatic, illustrating the retort and its associated elements. Figure 3 is an enlarged section of the retort. Figure 4 is an enlarged section of the retort taken online 4-4 in Figure 3. Figure 5 is a side view of timbers treated according to the invention, illustrating the limitation of impregnation, and Figure 6 is an enlarged cross-section showing the poles with various degrees of impregnation.

In the drawings 10 is the retort, which is usually placed so that one or both ends can be opened adjacent to tracks, so that in the case of the handling of large timbers, such I In the drawing I show a retort adapted to take opposed piles of poles, and the initial groups of poles being at the center of the retort. lit will be evident that if a retort is made to take but one length of pole, the entrance of the inlet pipe will be placed at one end of the retort.

The poles are shown at 1.3 in Figures 1 and 3. Suitably situated in the retort is a perforated pipe 14 which is connected to the inlet pipe 15 which has a suitable shut-off valve 16 therein and is supplied by the inlet pipe 17 which is connected to the carburetor 18. The inlet feed pipe 15 is provided with a regulating valve 19 and a suitable check valve 20. The carburetor which furnishes a mixture of air and preservative in finely divided form receives its air from the air supply tank 21. which receives air under pressure from the air compressor 22, the hand valve 23 and the check valve 24 being arranged in the pipe 25 which connects the air compressor 22 with the air pressure supply tank 21.

The pipe 26, in which is the check valve 27, passesfromthe air pressure supply tank 21 and has its end 28 open, as by a slit 29 opening into the oil or other preservative, shown at 30, in thecarburetor 18. A. perforated pipe 31 also projects into the carburetor 18 near .the bottom thereof, and is connected to the air pressure supply tank 21 thru a valve 32 and a check valve 33. The oil or other preservative supplied to the carburetor thru a pipe 34 containing a suitable-valve 35 and a check valve 36, this pipe leading from the hydraulic pressurepump 37 which is connected by the feed pipe 38 to the supply tanks 39 and 40.

At a suitablepoint, preferably the bottom For the purpose of further assisting in 10- calizing the treatment with the mixture of air and preservative in finely divided form, a second outlet pipe 46 is arranged above the retort 10 with branch outlet pipes 47 communicating with the inside of the retort, each of the pipes 47 being provided with a valve 48, and these branch outlet pipes 47 being'spaced and usually arranged opposite .the branch outlet pipes 44, The two outlet pipes 42 and 46 carry air and preservative to suitable separators 49, and these separators divide the air and preservative and deposit the preservative again in the supply tanks 39 and 40. Suitable vent pipes 50 are arranged on the tanks 39 and 40.

Valves 51, which are stop valves, are spaced along the perforated pipe 14, and similar valves 52 are spaced along the exhaust pipe 41 and preferably opposite the valves 51, for purposes to be hereinafter described.

One end of the perforated pipe 14 is connected by the pipe 53 to the inlet pipe 15 and is also connected to the steam supply pipe 54, and the valves 55 and 56 are provided to regulate the passage of the steam into the inlet plpe. A vacuum pump 57 is connected by a pipe 58 containing a valve 59, to one of the outlet pipes, the drawing showing it connected to the outlet pipe 46. The retort 10 has ends 60, one or both of which can be or perhaps longer, depending on the condition of the material, whether green or partly seasoned. During this steaming treatment the valves 54' and 55, and all of the valves 51 are open, thereby allowing steam to flow from the steam supply pipe 54 to and through the perforated pipe 14 from which the steam passes into the retort 10. While the steam is passing into the retort the valves 16, 43, 48 and all of the, valves 45 except that at k are preferably kept closed, and the water condensing from the steam inside the retort escapes through the valve 45 at k to the pipe 42 and out thru the blow-off valve 61. At the conclusion of the steaming period, the valve 54' is closed thereby shutting off the supply of steam, and the inside of the retort 10 is exhausted to a minimum of from 22 to 25 inches of mercury by means of vacuum pump 57, which is connected to the re tort thru the pipe 58. open valve 59, pipe 46 and one or more of the valves 48, all of the other valves controlling pipes leading to the retort being closed during this exhausting operation. After this vacuum treatment has been continued for the desired length of time, the vacuum pump 57 may be stopped and the pressure within the retort may be allowed to return to atmospheric pressure. llf desired, these steaming and exhausting treatments may be repeated a number of times for the purpose of opening the pores of the timber and withdrawing from it moisture, thus making the timber highly receptive to impregnation by the preservative.

We will assume. for the purpose of clear description only, that the butt ends or large rap ends of the poles in the drawing are to be subjected to complete impregnation, say for a distance of ten feet. This is done by treating these butt ends of the poles, with a mixture of air and preservative in finely divided form, and for the purpose of providing this mixture the carburetor 18 is provided. By opening the valve 35 and operating the hydraulic pump 37 the latter is caused to force preservative, such as creosote, from the supply tanks 39 and 40 into the carburetor 18; and at the same time, the valve 24 is'opened and the air compressor 22 forces air into the air supply tank 21 until a pressure of about one hundred and fifty pounds per square inch is obtained, where upon the valves 63 and 32 are opened to allow air pressure to be built up in the carburetor 18.

When pressure is equalized in both the carburetor "18 and the air pressure tank 21, the valves 19 and 16 are opened, which allows the mixture of air and preservative in finely divided form to escape from the carburetor 18 and discharge into the retort 10 through the perforated pipe 14.

Assuming that the valves 51, indicated at a, a, are shut, that the valves 52at b and f are shut, that the valve 43 at g is open, that the valves 45 at c are open and that the valves 48 at d are, open, the mixture of air and preservative injected into the retort will be localized between planes XX and YY. and the timber within this space will be thoroughly drenched with the preservative, which swirls around in the retort and does not pass beyond this-2e limitations; because the perfora' pipe 41 between the i alves at b and t f, the pipes 44 leading to the two open valves at c, c and the pipes 47 leading to the two open valves 48 at d, a? will act as exhausts and the preservative will not pass beyond these points, because the air beyond these points is trapped and acts a barrier, but will pass out into the outlet pipes 42 and 46 and pass back to the separators 49 and ultimately to the tanks 39 and 40. In other words. the air that is trapped in the ends of the retort 10 beyond the planes X-X and Y-Y prevents the heavier mixture of preservative and air from passing into those parts of the retort which are beyond such outlets.

In the first t of the impregnating proct-ss the temp ture of the mixture of air and preservati e in finely divided form is maintained at about 180 F. by means of heating coils, onc heating coil 64 being located in the air pressure supply tank 21, and the coil 65 being in the supply tank 40. This hot mixture of air and preservative heats the wood entirely thru, causing the air in the wood cells to expand, and opens up the pores. forming a partial vacuum within The temperature the mixture of air and preservative supplied to the retort is then reduced, in .any suitable manner, as by'substituting a cooling medium for a heating medium in the coils 64 and 65. When the woodxis cooled under treatment with the cape from the perforated pipe 14 as far toward the left as the valve 51 at At the same time, the valve 52 at f is opened, the

valve 52 at h is closed, and the valves 45 and 48 at e are opened, thereby permitting air and preservative to escape from the retort as far toward the left as the valve 52 at h. In

this way, the limit of impregnation is extended toward the left up to the line ZZ; and treatment of this additional length of the left group of poles may be continued as long as may be desired.

During the aforesaid treating operations the hydraulic pressure pump 37 is regulated to maintain, a constant level of the liquid. preservative in the carburetor 1'8, and the mixture of air and preservative in finely divided form forced into the retort will be constant. I may, if desired, place an automatic regulating valve (36, shown in dotted outline in Figure 2, in the feed pipe con nected by a branch pipe 67 to the retort, this valve 66 not being described in detail since they are in common use, this valve closing suddenly under a pressure of, say, one hundred pounds per square inch when such pres sure has been developed in the retort, and remaining closed until the pressure in the retort falls substantially to that of the atmosphere. The valve 66 then automatically opens once more and the pressure is again raised by the incoming mixture of air and. liquid preservative until the predetermined pressure for which the valve is set is again reached, and the valve is again automatically closed and the pressure again allowed to fall.

This alternate building up and releasing of pressure, when repeated for from two to five hours, depending on whether the timber is green or seasoned, causes the air to exhale from the pores of the wood, which opens up the pores, whereby each time the pressure is built up these pores are filled withair fully charged with the liquid preservative. This assists in thorough penetration of the wood.

As will be obvious to those skilled in the art of wood impregnation, the treatments hereinbefore described may be modified in many respects, depending upon thekind of Wood to betreatec', the extent to which such wood is seasoned, the nature of the preservative used and the depth to which it is desired to impregnate the wood. At the conclusion of the treatment, the pressure Within the retort may be restored to the same pressure as the atmosphere, and the treated timbrs may be removed from the retort tliru one of the ends which may be removed for that purpose.

It will, of course, be evident that suitable gages and thermometers for observing the temperature and pressures will be installed on the apparatus at suitable points, but these are not illustrated in the drawings.

To clearly illustrate the possibilities of the invention I show, in Figure 5 poles, the upper one having the butt end- 67 saturated for a material distance, the middle one having the butt end 68 saturated for only a short distance, and the lower one having the butt end saturated for a short distance and a further portion impregnated to a. certain depth.

It will, of course, be evident that slight variations can be made in the arrangement and proportion of the parts without departing from the scope of the invention.

1 claim:

1. A method of impregnating a portion of a timber which includes placing the whole timber in a closed retort, maintaining around that portion of the timber to be treated an atmosphere containing preservative n finely divided form, maintaining around that portion of the timber not to be treated an atmosphere substantially free of preservative, and applying pressure to the contents of the retort.

2. A method of impregnating a portion of a timber which includes placing the whole timber in a closed retort, injecting into the retort at points adjacent that portion of the timber to be treated a mixture of air and preservative in finely divided form, removing from the retort at points adjacent the portion of the timber to be treated air injected into the retort with the preservative, and applying pressure to the contents of the retort during treatment.

3. A method of impregnating a portion of a timber which includes placing the whole timber in a closed retort, injecting into the retort at points adjacent that portion of the timber to be treated a mixture of air and preservative in finely divided form, simultaneously allowin air to escape from the retort at points ad acent the portion of timber to be treated whereby the preservativeis confined to that portion of the timber to be treated. 1

4. The method of impregnating a portion of a timber which consists in placlng the whole timber in a closed retort, passing thru the retort around the portion of the timber to be treated a mixture of air and preservative in finely divided form, and applying pressure to the contents of the retort during treatment.

5. The method of impregnating a portion of a timber which consists in placing the whole timber in a substantially horizontal position in a closed retort, injecting into and removing from the retort at points adjacent that portion of the timber to be treated a mixture of air and preservative in finely divided form, and applying pressure to the contents of the retort during treatment.

6. The method of impregnating a portion of a timber which includes placing the whole timber in a substantially horizontal position in a closed retort, injecting into the retort at points adjacent that portion of the timber to be treated a mixture of air and preservative in finely divided form, simultaneously allowing air and preservative to escape from the retort at points adjacent the portion of the timber to be treated, and controlling the injection and escape of air and preservative so that the pressure will be periodically raised and lowered within the retort.

7 Apparatus for impregnating a portion of a timbercomprising a substantially horizontal retort adapted to receive the whole timber, means for injecting into the retort adjacent the portion of the timber to be treated a mixture of air and preservawithdrawing air from the retort adjacent the portion of the timber to be treated.

8. Apparatus for impregnating a portion of a timber comprising a substantially horizontal retort adapted to receive the whole timber, means for injecting into and withdrawing from the retort adjacent the portion of timber to be treated a mixture of air and preservative in finely divided form, and means for controlling the pressure existing 11 within the retort by reason of the injection and withdrawal of air and preservative.

9. Apparatus for impregnating a portion of a timber comprising a retort adapted to receive the whole timber in a substantially 115 horizontal position, means for injecting into the retort adjacent the portion of timber to be treated a mixture of air and preservative inseam ing thru the retort at the part thereof containing the portion of the timber to. be treated a mixture of air and preservative in finely divided form, and means for regulating the pressure within-the retort.-

11. Apparatus for impregnating a pore tion of a timber comprising a retort adapted.

to receive the whole timber. in a substantially horizontal position, means for injecting into the retort throughout any desired portion of its length a mixture of air and preservative in finely divided form,'means for withdrawing air from the retort throughout any desired portion of its length, and

means for controlling the injection of air and preservative and the withdrawal of air.

12. Apparatus for impregnating apor-.' tion of a timber comprising a retort adapted to receive thewhole timber in-a substantially horizontal position, a perforated pipe located within the retort near the top thereof, valves; located at intervals in said pipe means for supplggng a-mikture pf'lair and preservative in ely divided form to; said pipe, another perforated pipe extending longitudinally ofthe retort and located near the bottom thereof and leading out ofsaidretort, valves'located at intervals in saidpipe whereby the efiective length of the latter may be controlled, and an outlet from said -re-.

tort for v'vithdrawingg; accumulations of liq: uid preservative therefrom. 7

13. The combination of a carburetor for supplying under'pressure "air saturated with preservative, and a retort adapted to receive a whole timber in substantially horizontal position, said retort bein provided with means for receiving from t e carburetor the preservative-saturated air and passing ,it thru the retort at the art-thereof containing the portion of the timber to be treated.

14. The combination of a carburetor for supplying under pressure air saturated with preservative, and a retort adapted to receive a whole timber in substantially horiz ontal position, said retort being providedwith means for receiving from the curbureter the preservative-saturated air and passing it thru the retort at the part thereof containing the portion of the timber to be treated, and means for automatically controlling the supply of preservative-saturated air to the retort so that the pressure in the latter will be periodically raised and lowered.

15. The combination of means for supplying under pressure air saturated with a preservative, andv a retort adapted to receive a whole timber in a substantially horizontal position said retort being provided with means tor-admitting the preservativesaturated air throughout a certain portion of its length and with means for permitting leakage of air from the retort throughout a portion of its length corresponding to the portion throughout which the preservative,

saturated air enters.

516, The combination of means for supplying" under. pressure air saturated with a preservative, and a retort adapted to receive a whole timber in a substantially horizontal position, said. retort being provided with -means I for admitting the preservative-saturated air throughout a certain portion of its length and with means for permitting leakage 0 air from the retort throughout a portion of its length corresponding to the portion throughout which the preservativesaturated air enters, and a valve actuated in response to pressure'within the retort for my hand, this 10t day of f 

